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Inventories
3 Months Ended
Mar. 31, 2017
Inventory Disclosure [Abstract]  
Inventories
Inventories
(In millions)
March 31,
2017
 
December 31,
2016
Crude oil and refinery feedstocks
$
2,148

 
$
2,208

Refined products
2,674

 
2,810

Materials and supplies
414

 
485

Merchandise
156

 
153

Total
$
5,392

 
$
5,656


Inventories are carried at the lower of cost or market value. The cost of inventories of crude oil and refinery feedstocks, refined products and merchandise is determined primarily under the LIFO method. There were no liquidations of LIFO inventories for the three months ended March 31, 2017 and 2016.